Sökning: "heat pumps"

Visar resultat 21 - 25 av 98 avhandlingar innehållade orden heat pumps.

1. 21. HFC Mixtures as Replacement for HCFC-22 in Large-Scale Heat Pumps and Chillers

   Författare :Cecilia Gabrielii; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; R404A; R143a; R125; performance; R134a; R32; replacement; zeotropic HFC mixtures; simulations; design; measurements; chiller; R407C; condenser evaporator; screening; optimization; heat pump; R22;

   Sammanfattning : Replacement of the conventional refrigerant HCFC-22 (R22) is one of the urgent issues to be solved within the scheduled time-frame of the international regulation of the HCFCs. Since there exists no pure fluid that can replace R22 in the same general way as HFC-134a (R134a) is a replacement for CFC-12, HFC mixtures are suggested as possible substitutes. LÄS MER

3. 22. Evaluation of Modular Thermally Driven Heat Pump Systems

   Författare :Corey Blackman; Eva Thorin; Chris Bales; Christian Schweigler; Mälardalens universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sorption heat pump; sorption module; thermochemical energy storage; artificial neural network; built environment; solar energy; gas-driven heat pump; solar cooling; heating and cooling; renewable energy; energy efficiency; experimental; simulation; analytical; Energy- and Environmental Engineering; energi- och miljöteknik; Reesbe företagsforskarskola;

   Sammanfattning : The building sector accounts for approximately 40% of primary energy use within the European Union, therefore reductions in the energy use intensity of this sector are critical in decreasing total energy usage. Given that the majority of energy used within the built environment is for space conditioning and domestic hot water preparation, prudence would suggest that decreasing primary energy used for these end purposes would have the biggest overall environmental impact. LÄS MER

4. 23. Capacity Control of Residential Heat Pump Heating Systems

   Författare :Fredrik Karlsson; RISE; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; energy efficiency; variable-speed; air-source; performance; hydronic heating system; ground-source; heat pump; defrost; optimisation; circulator; capacity control;

   Sammanfattning : Heat pumps used for space and sanitary hot water heating of residential buildings are increasingly popular in northern Europe. As they compete with other heating equipment and in order to limit the environmental impact of their use, it is very important that heat pumps are energy efficient. LÄS MER

5. 24. Compression/Absorption cycles for large heat pumps - Systems simulations

   Författare :Lena Åhlby; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The compression/absorption cycle can, in many situations,give an improved performance compared to the single-fluidcompression heat pump. Also other advantages can beachieved such as the possibility to use an already knownrefrigerant within a new temperature range. LÄS MER

7. 25. Technical solutions for low-temperature heat emission in buildings

   Författare :Adnan Ploskic; Sture Holmberg; Bjarne Olesen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Analytical and numerical modeling; baseboard skirting heating; building energy performance; computational fluid dynamics CFD ; heat transfer; low-temperature heating; space heating; thermal comfort; Järnvägsgruppen - Effektiva tågsystem för godstrafik; Järnvägsgruppen - Effektiva tågsystem för godstrafik;

   Sammanfattning : The European Union is planning to greatly decrease energy consumption during the coming decades. The ultimate goal is to create sustainable communities that are energy neutral. One way of achieving this challenging goal may be to use efficient hydronic (water-based) heating systems supported by heat pumps. LÄS MER